Method and apparatus for cell measurement in a communications system

ABSTRACT

Disclosed are methods for performing radio measurements in a wireless device and methods in a network node for managing radio measurements performed by a wireless. Also disclosed are a network node and a wireless device suitable for performing the disclosed methods. A wireless device obtains an indication of a first cell carrier frequency associated with a first altitude range and an indication of a second cell carrier frequency associated with a second altitude range, determines an altitude of the wireless device and performs a radio measurement on a signal received from a cell operating on the first cell carrier frequency only when the altitude of the wireless device is within the first altitude range and performing a radio measurement on a signal received from a cell operating on the second cell carrier frequency only when the altitude of the wireless device is within the second altitude range.

TECHNICAL FIELD

Embodiments herein relate generally to a base station and a method inthe base station, and to a User Equipment (UE) and a method in the UE.More particularly the embodiments herein relate to radio communications,and in particular to managing radio measurements of cells.

BACKGROUND

Radio measurements are performed by a wireless device. For example aUser Equipment (UE) performs measurements on radio signals of one ormore cells (e.g. serving and neighbour cells) for one or more operationsor tasks e.g. mobility, positioning, minimization of drive tests (MDT),self-organising networks (SON), automatic neighbour relations (ANR) etc.In idle state, for example in 3GPP Radio Resource Control (RRC) IDLE,the UE performs measurements for operations such as cell selection, cellreselection (e.g. between base station cells on the same or differentcarriers, between cells of different Radio Access Types (RATs) etc.),minimization of drive test (MDT), positioning etc. In connected state(e.g. RRC CONNECTED) the UE performs measurements for operations such ascell change (e.g. handover between cells on the same or differentcarriers, between cells of different RATs), positioning, self-organisingnetworks (SON), signal to noise ratio (SNR).

The UE must first detect a cell, also known as cell identification. Thismay include acquisition of a physical cell identity (PCI) beforeperforming the measurement. Radio measurement may include signalstrength, strength quality, timing related measurement. The UE may alsohave to acquire the cell global ID (CGI) of a node (or cell). The cellidentification and CGI acquisition are also measurements. Examples ofsignal strength are reference signal received power (RSRP), narrowbandreference signal received power (NRSRP), sidelink reference signalreceived power (S-RSRP) path loss etc. Examples of signal quality arereference signal received quality (RSRQ), narrowband reference signalreceived quality (NRSRQ), reference signal-signal to Interference andnoise ratio (RS-SINR), received signal strength indicator (RSSI).Examples of timing related measurements are: timing advance, UE Receive(Rx)-Transmit (Tx) time difference, reference signal time difference(RSTD), and round trip time.

In connected state the UE can perform intra-frequency measurementswithout measurement gaps. However, as a general rule the UE performsinter-frequency and inter-RAT measurements in measurement gaps. Toenable inter-frequency and inter-RAT measurements for the UE requiringgaps, the network must configure the measurement gaps. For example, in3GPP Long Term Evolution (LTE) two periodic measurement gap patterns(with 40 ms and 80 ms periods) each with a measurement gap length of 6ms are defined for LTE.

The measurements performed by the UE are then normally reported to thenetwork, which may use them for various tasks.

Notwithstanding aviation regulations pertaining to the use of wirelessradio devices on commercial aircraft, the provision of Mobile Broadband(MBB) applications to wireless device associated with an aerial vehiclesuch as an aeroplane, generates two main challenges. One issue isseamless connectivity, for example to provide a seamless MBB experiencein-cabin, to a UE connected to the in-cabin system from a terrestrialcellular network. It is foreseen that the aforementioned regulationscould change to permit use of terrestrial mobile networks by commercialaircraft for in-cabin MBB. This may be provided by an in-cabin networkconnected to the terrestrial mobile network, for example a Wi-Fi networkwhere only Wi-Fi transceivers are enabled or direct connectivity ofpassenger's UEs to the terrestrial mobile network, or both. It isdesirable to maintain the session continuity handing over from mobilenetwork operator (MNO)'s terrestrial network (i.e. a Public Land MobileNetwork, PLMN) to the in-cabin network. One challenging issue is relatedto interference between terrestrial and in-cabin networks, which dependson the spectrum used in the in-cabin network and the terrestrialnetwork. An in-cabin network may comprise small cell wireless transmitand receive points. Another issue is high-performance aircraftback-haul, to enable high capacity MBB to wireless devices associatedwith an aerial vehicle. Solutions need to provide an air-to-ground (A2G)link which is capable of extremely high capacity in terms of bitrate (toaccommodate a large number of passengers on board) and also reasonableRTT delay such that real time applications can be supported.

Currently, A2G links are based on satellite backhaul. Due to lowcapacity satellite communications, there are large RTT delays whichhinders real-time user experience; also, due to capacity issues, highdata rate applications are not possible or cost effective. Satellitecommunications are inefficient for the backhaul due to multiple linksbeing required to offer sufficient capacity. In addition a completelyseparate in-cabin (typically GSM) mobile network, is required, whichcould be costly for deployment. The system also requires special groundmobile network interference protection.

One possibility for an air-to-ground system can be based on 3GPP NewRadio (NR) and/or evolved LTE. For obtaining a high capacity link,between the terrestrial base station and an aerial vehicle, beamformingtechnologies can be exploited and new frequencies where highertransmission bandwidth may be available.

FIG. 1 shows a typical network, 10, where aerial vehicles, 60, havewireless devices (20) onboard and wherein the air to ground backhaul isprovided by either a satellite, 50, via a satellite ground station, 40or provided by a mobile terrestrial network such as LTE comprising radiobase stations, 30. Examples of aerial vehicles vary from commercialaeroplanes carrying many wireless devices (which may be served by alocal wireless network) to unmanned aircraft such as drones, possiblycarrying only one or two wireless devices. The wireless devices may bepersonal communications devices or may be an integrated wireless devicewithout any human user interface.

The A2G backhaul link may be replaced by cellular based technologies,such as 3GPP LTE or NR (5G Radio access). Using LTE and/or NR canprovide higher capacity/and/or frequency reuse , specifically, by makingusing of LTE and/or NR beamforming technology for air-to-ground links.This will also ensure lower costs and seamless connectivity throughintegration with ground mobile networks. New features in LTE and NR areneeded for managing radio networks interference between A2G link,in-cabin network and terrestrial mobile networks, e.g. PLMNs.

A UE performs radio measurements (e.g. path loss, RSRP, RSRQ etc.) onsignals of one or more carrier frequencies which are received by the UE.The UEs are typically assumed to be on ground level or in high risebuildings. The introduction of aerial vehicles with integrated wirelessdevices (e.g. drones) and aeroplanes, helicopters etc. whereinpassengers are permitted to use their wireless devices will require thenetwork to deploy cells with coverage also in the vertical dimension.However some of the cells may still have coverage mainly in horizontalplane with limited coverage in the vertical dimension.

The deployment of cell coverage in both the vertical and horizontal willhowever also increase UE complexity in terms of mobility procedure whichmainly relies on the UE radio measurements of neighbour cells, thedensity of which would increase if vertical cells are deployed over thetop of horizontal cells Therefore a new mechanism is needed for ensuringthat good UE mobility performance is achieved under such scenario (i.e.comprising of a mixture of vertical and horizontal cells).

In U.S. Pat. No. 9,357,552 B1 networks are adjusted based on thealtitude of wireless communication devices. The methods discloseddetermine the number of wireless communication devices are certainaltitudes and allocate resources, for example transmit power orfrequencies in response to the determined number of wirelesscommunication devices at certain altitudes.

In U.S. Pat. No. 8,639,265 B1 a radio access network (RAN) is disclosedwhich determines the altitude of a wireless communications device andsignals a neighbour cell list which is limited to cells and orfrequencies which apply to the altitude of said wireless communicationsdevice.

SUMMARY

An embodiment provides a method for performing radio measurements in awireless device in a communications system comprising at least onenetwork node. The method comprises obtaining an indication of a firstcell carrier frequency associated with a first altitude range and anindication of a second cell carrier frequency associated with a secondaltitude range. The method further comprises determining an altitude ofthe wireless device and performing a radio measurement on a signalreceived from a cell operating on the first cell carrier frequency onlywhen the altitude of the wireless device is within the first altituderange and performing a radio measurement on a signal received from acell operating on the second cell carrier frequency only when thealtitude of the wireless device is within the second altitude range. Theembodiment provides the advantage that the number of cell measurementsthe UE needs to perform is reduced but does so without the networkproviding the UE with an explicit indication of cells it may measure,e.g. via a neighbour cell list. This provides the further advantage thatthe network only needs to allocate cells with a certain carrierfrequency which it has assigned to provide altitude specific service,rather than dedicate a specific cell ID to an altitude directly. Thisprovides an efficient method of managing radio measurements performed bywireless devices since the wireless devices do not need to inform thenetwork of their altitude to determine whether or not they are permittedto perform a radio measurement on a detected cell. In some embodimentsthe carrier frequencies are reserved for specific altitudes. In otherexamples the carrier frequencies may be re-allocated to differentaltitudes depending certain network criteria, for example the networkload, distribution of served UEs.

In some examples the first altitude range is indicated by a firstaltitude value and a first threshold parameter, wherein the firstthreshold parameter indicates whether the first altitude range is aboveor below the first altitude value and the second altitude range isindicated by a second altitude value and a second threshold parameter,wherein the second threshold parameter indicates whether the secondaltitude range is above or below the second altitude value. For examplethe first threshold parameter indicates the altitude range is valid forany UE with an altitude below the first altitude value, say 2000 metresand the second altitude threshold parameter indicates the altitude rangeis valid for any UE with an altitude above the second altitude value,say 2500 metres.

In other examples the second altitude range starts immediately after theend of the first altitude range and/or the first altitude range isentirely below the second altitude range.

In other examples the method further comprises reporting the radiomeasurement to the network node.

In other examples the method comprises reporting an information aboutthe altitude or the altitude range of the wireless device at which thewireless device performed the radio measurement.

In other examples the method comprises receiving a data service from thenetwork node wherein the data service is based on the reported radiomeasurement and/or the reported information about the altitude or thealtitude range of the wireless device.

In some examples the obtaining the indication of the first cell carrierfrequency and the indication of the second cell carrier frequency is bya dedicated or broadcast signal from the network node.

In some examples the wireless device performs a radio resourcemanagement or a mobility management operation based on the radiomeasurement and/or the altitude or the altitude range of the wirelessdevice.

In an embodiment a method in a network node for managing radiomeasurements performed by a wireless device, e.g. a UE, in acommunications network is provided. The method comprises determining anassociation of a first cell carrier frequency to a first altitude rangeand an association of a second cell carrier frequency to a secondaltitude range. The method further comprises providing the wirelessdevice with an indication of the first cell carrier frequency associatedwith the first altitude range and an indication of the second cellcarrier frequency associated with the second altitude range. Thisembodiment provides the advantage that the network node can manage cellsfor providing service to UEs based on the altitude of the UE. Further,the network node does not need to know the altitude of the UE, it relieson the UE only performing radio measurements on a cell when it is in thealtitude range allowed for that cell.

In other examples the method comprises receiving, from the wirelessdevice, a measurement report comprising at least one radio measurementperformed by the wireless device, wherein the radio measurement is onlyperformed on a signal from a cell operating on the first cell carrierfrequency when the altitude of the wireless device is within the firstaltitude range and only performed on a signal received from a celloperating on the second cell carrier frequency when the altitude of thewireless device is within the second altitude range.

In some examples the method further comprises receiving from thewireless device an information about the altitude or the altitude rangeof the wireless device at which the wireless device performed the atleast one radio measurement.

In some examples the method further comprises providing a data serviceto the wireless device wherein the data service is based on the reportedat least one radio measurement and/or based on the received informationabout the altitude or the altitude range of the wireless device.

In some examples the wireless device is instructed to perform a radioresource management or a mobility management operation based on thereported at least one radio measurement and/or based on the receivedinformation about the altitude or the altitude range of the wirelessdevice.

In some examples the first altitude range is indicated by a firstaltitude value and a first threshold parameter, wherein the firstthreshold parameter indicates whether the first altitude range is aboveor below the first altitude value; and the second altitude range isindicated by a second altitude value and a second threshold parameter,wherein the second threshold parameter indicates whether the secondaltitude range is above or below the second altitude value.

In some examples the second altitude range starts immediately after theend of the first altitude range and/or the first altitude range isentirely below the second altitude range.

In some examples the method further comprises determining theassociation of the first cell carrier frequency to the first altituderange and the association of the second cell carrier frequency to thesecond altitude range based on one or more of: cell coverage; beamcharacteristics; frequency range or band; and antenna characteristics.

In some examples the providing the indication of the first cell carrierfrequency and the indication of the second cell carrier frequency issignalled by a dedicated or broadcast signal.

In an embodiment a wireless device for performing radio measurements ina communications system comprising at least one network node isprovided. The wireless device is configured to obtain an indication of afirst cell carrier frequency associated with a first altitude range andan indication of a second cell carrier frequency associated with asecond altitude range. The wireless device determines the altitude ofthe wireless device and performs a radio measurement on a signalreceived from a cell operating on the first cell carrier frequency onlywhen the altitude of the wireless device is within the first altituderange and perform a radio measurement on a signal received from a celloperating on the second cell carrier frequency only when the altitude ofthe wireless device is within the second altitude range.

In an embodiment a network node for managing radio measurementsperformed by a wireless device in a communications network is provided.The network node is configured to determine an association of a firstcell carrier frequency to a first altitude range and an association of asecond cell carrier frequency to a second altitude range. The networknode is further configured to provide the wireless device with anindication of the first cell carrier frequency associated with the firstaltitude range and an indication of the second cell carrier frequencyassociated with the second altitude range.

In some examples the network node is further configured to receive, fromthe wireless device, a measurement report comprising at least one radiomeasurement, wherein a radio measurement is only performed on a signalfrom a cell operating on the first cell carrier frequency when thealtitude of the wireless device is within the first altitude range and aradio measurement is only performed on a signal received from a celloperating on the second cell carrier frequency when the altitude of thewireless device is within the second altitude range.

In an embodiment, an apparatus for performing radio measurements in acommunications system comprising at least one network node is provided.The apparatus comprises a processor, a memory, and a transceivercircuit. The transceiver circuit is configured to obtain an indicationof a first cell carrier frequency associated with a first altitude rangeand an indication of a second cell carrier frequency associated with asecond altitude range. The processor is executable to determine thealtitude of the wireless device. The transceiver circuit is furtherconfigured to perform a radio measurement on a signal received from acell operating on the first cell carrier frequency only when thealtitude of the wireless device is within the first altitude range andperform a radio measurement on a signal received from a cell operatingon the second cell carrier frequency only when the altitude of thewireless device is within the second altitude range.

In another embodiment, an apparatus for managing radio measurementsperformed by a wireless device in a communications network is provided.The apparatus comprises a processor, a memory, and a transceivercircuit. The processor is configured to determine an association of afirst cell carrier frequency to a first altitude range and anassociation of a second cell carrier frequency to a second altituderange. The transceiver circuit is configured to provide, to a wirelessdevice, an indication of a first cell carrier frequency associated witha first altitude range and an indication of a second cell carrierfrequency associated with a second altitude range.

In another embodiment a wireless device control application is provided.The wireless device control application comprises a transceiver module,a determination module, and a measurement module. The Transceiver moduleis configured to obtain an indication of a first cell carrier frequencyassociated with a first altitude range and an indication of a secondcell carrier frequency associated with a second altitude range. Thedetermination module is configured to determine the altitude of thewireless device. The transceiver module is configured to perform a radiomeasurement on a signal received from a cell operating on the first cellcarrier frequency only when the altitude of the wireless device iswithin the first altitude range and perform a radio measurement on asignal received from a cell operating on the second cell carrierfrequency only when the altitude of the wireless device is within thesecond altitude range.

In other examples the wireless device control application comprises theaforementioned modules and/or other modules configured to perform any ofthe methods disclosed herein.

In another embodiment a network node control application comprising atransceiver module and a determination module is provided. Thedetermination module is configured to determine an association of afirst cell carrier frequency to a first altitude range and anassociation of a second cell carrier frequency to a second altituderange. The transceiver module is configured to provide, to a wirelessdevice, an indication of a first cell carrier frequency associated witha first altitude range and an indication of a second cell carrierfrequency associated with a second altitude range.

In other examples the network node control application comprises theaforementioned modules and/or other modules configured to perform any ofthe methods disclosed herein.

In another embodiment a computer program or, a computer program productor a carrier containing a computer program, comprising instructionswhich, when executed on at least one processor, causes the at least oneprocessor to carry out a method according to any one of the examplesdisclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example network environmentaccording to the prior art.

FIG. 2 is a block diagram illustrating embodiments of the presentdisclosure.

FIG. 3 is a signaling sequence according to embodiments of the presentdisclosure.

FIG. 4 is a flow diagram illustrating an exemplary method implemented bya wireless device according embodiments of the present disclosure.

FIG. 5 is a flow diagram illustrating an exemplary method implemented bya network node according to embodiments of the present disclosure.

FIG. 6 is a block diagram illustrating example hardware useful forimplementing the methods described herein, according to one or moreembodiments of the present disclosure.

FIG. 7 is a block diagram illustrating example hardware useful forimplementing the methods described herein, according to one or moreembodiments of the present disclosure.

FIG. 8 is a block diagram illustrating example physical units ofprocessing circuitry of a wireless device useful for implementing themethods described herein, according to one or more embodiments of thepresent disclosure.

FIG. 9 is a block diagram illustrating example physical units ofprocessing circuitry of a network node useful for implementing themethods described herein, according to one or more embodiments of thepresent disclosure.

FIG. 10 is a block diagram illustrating example software modules of awireless device control application useful for implementing the methodsdescribed herein, according to one or more embodiments of the presentdisclosure.

FIG. 11 is a block diagram illustrating example software modules of anetwork node control application useful for implementing the methodsdescribed herein, according to one or more embodiments of the presentdisclosure.

DETAILED DESCRIPTION

In some embodiments a more general term “network node” is used and itcan correspond to any type of radio network node or any network node,which communicates with a User Equipment (UE) and/or with anothernetwork node. A network node may comprise a radio access network, RAN,or a radio base station, or part thereof such as a remote antenna unit.Other examples of network nodes, or known terms for radio access nodesare NodeB, enhanced NodeB (eNodeB or eNB), base transceiver station(BTS), access point (AP), transmission and reception points, TRPs,remote radio unit, RRU, Remote Radio Head, RRH, nodes in distributedantenna system (DAS). A network node may also comprise core network node(e.g. Mobile Switching Centre, MSC, Mobility Management Entity, MME,etc.), O&M, Operation Support Systems, OSS, Self-Organised Networks,SON, positioning node (e.g. Enhanced Serving Mobile Location Centre,E-SMLC), Minimisation of Drive Test, MDT, test equipment, etc.

In some embodiments the non-limiting term wireless device is used and itrefers to any type of wireless device communicating with a network nodeand/or with another wireless device. Examples of a wireless device are“user equipment” (UE) which includes device to device (D2D) UE, machinetype communication (MTC) UE or UE capable of machine to machine (M2M)communication, Personal Digital Assistant (PDA) tablet computer, mobileterminals, smart phone, laptop embedded equipped (LEE), laptop mountedequipment (LME), Universal Serial Bus (USB) dongles.

Some embodiments are described using terms from 3^(rd) GenerationPartnership Project (3GPP) Long Term Evolution (LTE) or LTE basedsystems such as Machine Type Communication (MTC), enhanced MTC,Narrowband Internet Of Things (NB-IoT). However the embodiments areapplicable to any Radio Access Type (RAT) or multi-RAT systems, wherethe wireless device receives and/or transmit signals (e.g. data) ExampleRATs are: LTE Frequency Division Duplex (FDD)/Time Division Duplex(TDD), Wideband Code Division Multiple Access (WCDMA)/High Speed PacketAccess (HSPA), Groupe Spécial Mobile (GSM)/GSM Edge Radio Access Network(GERAN), Wi-Fi, WLAN, CDMA2000, 5G, New Radio (NR).

5G, the fifth generation of mobile telecommunications and wirelesstechnology is not yet fully defined but in an advanced draft stagewithin 3GPP. It includes work on 5G New Radio (NR) Access Technology.LTE terminology is used in this disclosure in a forward looking sense,to include equivalent 5G entities or functionalities although adifferent term may be specified in 5G. A general description of theagreements on 5G New Radio (NR) Access Technology so far is contained inmost recent versions of the 3GPP 38-series Technical Reports.

Embodiments disclosed are applicable for a wireless device, or UE, in alow or in high activity state. Examples of low activity state are RRCidle state, idle mode etc. Examples of high activity state are RRCCONNECTED state, active mode, active state etc. The UE may be configuredto operate in discontinuous reception (DRX) or in continuous reception(non-DRX). If configured to operate in DRX, it may still operateaccording to non-DRX as long as it receives new transmissions from thenetwork node.

In some examples, a wireless device or UE can be a transceiver stationlocated in a flying vehicle, with a non-limiting term: FlyingTransceiver Station (FTS).

In a cellular system such as LTE, LTE evolution, or NR where certaincells may be adapted to provide a vertical cell coverage up to 100 km,wireless devices in high altitude aerial vehicles may rely solely onradio communication rather than satellite. However, as the various typesof aerial vehicle with wireless device capability, such as drones forexample, traverse these cells the wireless device should perform radiomeasurements on the cells it detects. In LTE for example the UE is notdirected to a list of neighbour cells, rather it performs measurementson any cell detected. An example of such a scenario network, 100, isdepicted in FIG. 2 where a base station, 120, provides three cells atfrequencies F1, F2 and F3. It should be understood that the scenario mayalso be depicted with 3 separate base stations. Aerial vehicles, 130,140, 150, traverse the radio coverage provided by the base station anddepending on the altitude the wireless devices, 110, therein may detectand perform measurements on one, two or all three of the cells. Alsodepicted is a land based wireless device, 160, which is able to detecttwo of the cells, F1 and F3.

In some examples it is desirable to dedicate certain cells to certainaltitudes. This can be achieved to some degree through multiple antennasystems providing beamforming, however there can still be some overlapor interference between terrestrial devices (i.e. devices within analtitude range intended to be served by a horizontal cell) and aerialdevices intended to be served by a vertical cell. This can be seen inFIG. 2 where the cells F1 and F3 are overlapping and can both bedetected by wireless devices in aerial vehicle 150 and terrestrialdevice 160.

By allocating cells operating on a certain frequency to a certainaltitude range, e.g. A1, A2, A3, a network node, e.g. radio accessnetwork, can control which devices perform and report measurements onwhich cells. This may be achieved by a radio access network, or networknode, signalling for each cell frequency a parameter indicative of thealtitude range associated to that cell.

The embodiments are described considering two carrier frequencies (F1and F2) and their respective altitude ranges. However these embodimentsare applicable for any number of carriers and their associations withrespect to their corresponding altitudes ranges. For example the networknode may further determine an association between a third carrier (F3)and a third altitude range. The actual association depends upon theheight over which a particular carrier frequency operates and/or overwhich the UE is allowed to perform measurements on that carrier.

In more detail, the network node determines associations between atleast one carrier frequency, F1, and at least one altitude parameter,H1, and between at least one carrier frequency, F2, and at least onealtitude parameter, H2. For example a cell operating on carrierfrequency F1 can provide or is allowed to provide network coveragewithin a range indicated by H1. In some examples H1 indicates a heightwith respect to a reference altitude (e.g. sea level, ground level,pre-defined altitude etc.) and thereby provides an altitude range fromthe reference altitude to height H1. Similarly a cell operating oncarrier frequency F2 can provide or is allowed to provide networkcoverage within a range indicated by H2. In some examples H2 indicates aheight with respect to a reference altitude (e.g. sea level, groundlevel, pre-defined altitude etc.) and thereby provides an altitude rangefrom the reference altitude to height H2. The altitude ranges mayoverlap or may be mutually exclusive. An overlapping range would permita land based wireless device measuring signals from either cellfrequency whereas an aerial wireless device once above the lower of thetwo ranges would cease to perform measurements on the frequencyassociated to the lower altitude range. A mutually exclusive rangeassociated with the two frequencies would entirely separate the landbased and aerial wireless devices at a certain altitude, for examplealtitude range A1 may be entirely below altitude range A1.

In other examples the altitude parameter, e.g. H1, H2 provides analtitude range by comprising two altitude values, i.e. a lower and anupper bound, each value with respect to a reference altitude such as sealevel.

In some examples the altitude parameter includes a threshold parameter.For example carrier F1 can provide or is allowed to provide networkcoverage only up to a certain height (H1) i.e. the threshold parameterindicates that H1 is an upper bound. Similarly, carrier F2 can provideor is allowed to provide network coverage above certain height (H2),i.e. the threshold parameter indicates that H2 is a lower bound. Aspreviously described the ranges may be overlapping or mutuallyexclusive. For example the second altitude range starts immediatelyafter the end of the first altitude range. In some examples the firstaltitude range is entirely below the second altitude range.

In FIG. 3 an example signaling sequence is shown. The network node orbase station, (BS) 120 at step 300 transmits the cell carrier frequencyto altitude association (e.g. {F1, H1}, {F2, H2}) to the wireless device(UE), 110. In some examples this is transmitted in a broadcast message,for example in system information, which is received by a plurality ofwireless devices. In other examples this is transmitted as dedicatedinformation to the UE 110, for example in a RRC configuration messagewhen the UE is in connected mode. In other examples the cell carrierfrequency to altitude association may be configured by a networkmanagement procedure for example via over-the-air (OTA) configuration.At step 310 the UE, 110, determines its altitude (Hu) and compares itwith the received or obtained parameters related to the altitudes (e.g.H1, H2) and determines whether the UE, 110, is allowed to performmeasurements on reference signals of cells operating on the carrierfrequency F1 and/or F2. There are many known methods for a wirelessdevice to determine its altitude, typically as part of standardpositioning methods. Such methods are described in more detail below. Atstep 320 and 330 the BS, 120, transmits reference signals RS1 and RS2,respectively. RS1 and RS2 may be any kind of reference signal upon whicha wireless device should perform radio measurements, for example cellspecific reference signals, demodulation signals, channel stateinformation reference signals. At step 340 the UE, 110, performs radiomeasurements on the reference signals if determined to do so thedetermined carrier(s) F1 and/or F2 and may use the results for one ormore operations. For example, the UE may adjust its measurement patternsand/or sleep cycles as a result of the determined cell frequencies onwhich it may or may not measure signals. At step 350 UE, 110, may reportmeasurements to its serving network node, 120. This step depends on thewireless device being configured to report radio measurements and alsowhether it receives reference signal from cells operating on carrierfrequencies which the UE, 110, has determined it is allowed to measure.In some embodiments the wireless device may also report its altitude tothe network node. At step 360 the network node may signal a radioresource control or mobility management message or command to UE, 110,as a result of the reported measurements. For example, the network nodemay command the wireless device to change its serving cell, or cells, ormay adjust the wireless device's measurement pattern and/or sleepcycles. The network node may also perform other tasks as a result of themeasurement report, for example the network node may switch onadditional transmission points or allocate additional resources (e.g.Coordinated Multi-point, CoMP, Heterogenous Network, HetNet, operation,carrier aggregation, CA).

The procedures performed by a wireless device will be discussed in moredetail, in conjunction with the method 400, depicted in FIG. 4. Themethod starts at step 410, for a wireless device served by one or morenetwork nodes, e.g. radio base stations, in a communications system. Thewireless device, e.g. a UE may be in IDLE mode or CONNECTED mode. Atstep 420 the wireless device obtains an indication of a first cellcarrier frequency associated with a first altitude range and anindication of a second cell carrier frequency associated with a secondaltitude range; In some examples the indication of a cell carrierfrequency is an actual frequency value ‘f’. In other examples theindication is a number which corresponds to the carrier frequency suchas the UTRA (UMTS (Universal Mobile Telecommunications System)Terrestrial Radio Access) Absolute Radio Frequency Channel Number(UARFCN) for WCDMA systems or Enhanced-UTRA RFCN for LTE systems. Insome examples the first and second altitude ranges are indicated by anupper and lower height, wherein the range allowed for the cell is withinthe two heights. Typically, a height indicates a vertical distance abovea reference, for example sea level. However, the reference height may beanother known value, for example the lowest ground level in the cell ora value configured by the network.

In some examples the indication of a first cell carrier frequencyassociated with a first altitude range and an indication of a secondcell carrier frequency associated with a second altitude range may bereceived by the wireless device in the same message or the indication ofa first cell carrier frequency associated with a first altitude rangemay be received in a different message to the indication of a secondcell carrier frequency associated with a second altitude range.

The information may be received on one or more cells operating on thecarrier frequencies F1 and/or F2. The information may also be receivedin one or more cells operating on another carrier frequency, e.g. F3.

In step 430 the wireless device or UE determines its altitude (Hu) withrespect to a reference altitude (G1). Examples of G1 are sea level,ground level in certain region, a value configured by the network node,a pre-defined value, the lowest point in a given region, the highestpoint in a given region etc. The wireless device or UE may determine itsaltitude by means of positioning techniques and/or based on informationreceived from another node.

Examples of such techniques are:

-   -   by using Global Navigation Satellite System (GNSS) receiver in        the UE,    -   by using an Assisted GNSS (A-GNSS) receiver in the UE,    -   by one or more non-GNSS positioning techniques e.g. enhanced        cell ID, Observed Time Difference of Arrival (OTDOA), Uplink        Time Difference of Arrival (UTDOA) etc.    -   combination of positioning techniques,    -   based on the altitude of the aerial vehicle housing the UE. For        example the UE may receive information about the altitude of        aerial vehicle and derive Hu from the received information about        the altitude. In one example the UE may assuming that Hu is        equal to the altitude of aerial vehicle housing the UE. In        another example the UE may derive Hu by using a pre-defined        mapping between UE altitude and the altitude of the aerial        vehicle housing the UE,    -   receiving parameter Hu from another node (e.g. another UE        capable of D2D operation etc.).

In step 440 the UE compares Hu and H1, and compared Hu and H2. Based onsaid comparison the UE determines whether the UE is allowed to performmeasurements on signals of F1 and/or on signals of F2. The selection ofF1 and F2 based on the said comparison is based on the same principle asdescribed in sections 5.2.2 (UE embodiment, Step 2).

In one example the UE is required to perform measurements only on F1provided that the UE altitude (Hu) is lower than H1 and the UE isrequired to perform measurements only on F2 provided that Hu is higherthan H2. The parameters H1, H2 and Hu are defined with respect to areference altitude (G1). Examples of G1 are sea level, ground level incertain region, a value configured by the network node, a pre-definedvalue, lowest point in a given region, highest point in a given regionetc. In one example H1=H2 whereas in another example H1≠H2 (e.g. H1<H2).

In another example when H1≠H2 (e.g. H1<H2), the UE is required toperform measurements only on F1 provided that Hu≤H1, the UE is requiredto perform measurements only on F2 provided that Hu>H2 and when Hu isbetween H1 and H2 then the UE is required to do measurements on both F1and F2.

In yet another example when H1≠H2 (e.g. H1<H2), the UE is required toperform measurements only on F1 provided that Hu≤H1, the UE is requiredto perform measurements only on F2 provided that Hu>H2 and when Hu isbetween H1 and H2 then the UE is required to do measurements on at leastone of F1 and F2. In the last case for example the UE may decide toperform measurement on the carrier (F1 or F2) whose signals arestrongest (e.g. in terms of signal strength and/or signal quality at theUE).

The measurements may be performed by the UE on signals of one or morecells operating on the carrier i.e. on signals of cells belonging to F1and/or F2. The measurements may also be performed on the entire carriere.g. RSSI, received carrier power etc.

The UE performs a radio measurement on a signal received from a celloperating on the first cell carrier frequency only when the altitude ofthe wireless device is within the first altitude range and performs aradio measurement on a signal received from a cell operating on thesecond cell frequency only when the altitude of the wireless device iswithin the second altitude range.

The measurements may be performed by the UE on signals of one or morecells operating on each determined or t selected carrier i.e.measurement on signals transmitted on cells belonging to F1 and/or F2.The signals used for measurements may be transmitted by the cell in theDL and/or by the UE in the uplink. Examples of cell specific or celllevel measurements are signal strength (e.g. RSRP, path loss etc.),signal quality (e.g. SNR, SINR, RS-SINR, RSRQ etc.), timing measurements(e.g. timing advance, propagation delay, UE Rx-Tx time difference, RSTDetc.).

The measurements may also be performed on the entire carrier i.e. onsignals of plurality of cells or of all cells belonging to thedetermined carrier. Examples of carrier specific or carrier levelmeasurements are RSSI, received carrier power etc.

As described above, in some embodiments the first altitude range isindicated by a first altitude value and a first threshold parameter,wherein the first threshold parameter indicates whether the firstaltitude range is above or below the first altitude value and the secondaltitude range is indicated by a second altitude value and a secondthreshold parameter, wherein the second threshold parameter indicateswhether the second altitude range is above or below the second altitudevalue.

The UE may receive altitude parameters indicating that the secondaltitude range starts immediately after the end of the first altituderange, thus providing seamless vertical coverage. In other examples theparameters indicate the first altitude range is entirely below thesecond altitude range but there may be a vertical distance between thetwo ranges.

In some embodiments the wireless device, or UE, reports the radiomeasurements for at least one signal received on a cell operating on acarrier frequency as permitted to be measured according to the rulespreviously described. In some examples the report comprises a pluralityof measurements on a plurality of signals on one or more cells operatingon one or more carrier frequencies.

In some embodiments the wireless device, or UE, reports informationabout the altitude or the altitude range of the wireless device at whichthe wireless device performed the above described radio measurement. Insome examples the wireless device transmits this information in the samereport as transmitted for the radio measurements, in other examples theinformation about the altitude or altitude range is transmitted in aseparate report.

In some embodiments the wireless device receives a data service from thenetwork node as a result of the reported radio measurement or thereported information about the altitude or the altitude range of thewireless device. Depending on the status of the wireless device (IDLEmode or CONNECTED mode) the response from the network node, e.g radiobase station will vary. For example the data service may be an initialservice by providing a random access response followed by dedicateresources/physical data channels. In other examples the data service maycomprise additional cells and associated dedicated resources to whichthe wireless device may connect. In other examples the data serviceprovided based on the reported measurements and/or altitude informationmay comprise a Mobile Broadband (MBB) application specifically tailoredto the altitude of the wireless device.

In other examples the network node or radio access initiates cell changeprocedures or handover of the wireless device to a neighbour cell.

In some embodiments the wireless device performs a radio resourcemanagement or a mobility management operation based on the radiomeasurement and/or the altitude or the altitude range of the wirelessdevice

The wireless device or UE may use the results of the radio measurementperformed on F1 and/or F2 for one or more operational tasks. Examples ofsuch tasks are:

-   -   Transmitting the measurement results to the network node,    -   Transmitting the measurement results to another UE capable of        D2D operation (e.g. ProSe operation, V2X operation etc.),    -   Performing cell change e.g. cell selection, cell reselection,        handover, RRC re-establishment, RRC connection release with        redirection,    -   Positioning etc.    -   Adaptation of receiver,    -   Power control etc.

FIG. 5 describes in more detail the procedures performed by networknode, through the steps of method 500. The method for managing radiomeasurements performed by a wireless device starts at step 510 where anetwork node, e.g. radio access such as eNodeB or gNb provides serviceto one or more wireless devices such as a UE. At step 520 the networknode determines an association of a first cell carrier frequency to afirst altitude range and an association of a second cell carrierfrequency to a second altitude range,

In other examples the network node determines one or more associations,based on one or more criteria. In some examples the network nodedetermines a first association or relation or mapping, which relates afirst carrier frequency (F1) to a first altitude parameter (H1), and asecond association or relation or mapping, which relates a secondcarrier frequency (F2) and a second altitude parameter (H2).

Examples of criteria for determining the associations are:

-   -   Cell coverage: Carriers which have larger coverage can be used        for serving UEs which are located inside or on an aerial vehicle        when the vehicle reaches above certain height. The cell coverage        can be extended by increasing for example transmit power of the        base station,    -   Beam characteristics: For example certain carrier may be served        by beams directed upwards towards the sky. These carriers can be        used for serving UEs which are located inside or on an aerial        vehicle when it reaches above certain height,    -   Frequency range or band: Certain frequencies may be suitable for        serving UEs on the ground or at lower height. For example        frequencies below 1 GHz which have better coverage may be used        for serving the UEs at lower height or on the ground. However,        carriers above 2 GHz can still be suitable for serving UEs at        higher altitude since the propagation condition is mainly line        of sight,    -   Antenna characteristics: If the base station has larger number        of transmit antennas (e.g. 8 or more antennas) then the signals        of carriers used by that base station can be beamformed. This        gives better directivity and coverage of signals. Such carriers        can be used for serving UEs which are located inside or on an        aerial vehicle when the vehicle reaches above certain height.

The associations define altitudes or altitude ranges over which thefirst cell carrier frequency, F1 and the second cell carrier frequency,F2 respectively, are allowed to be used by the UE for performing one ormore radio measurements.

At step 530 the network node provides the wireless device with anindication of a first cell carrier frequency associated with a firstaltitude range and an indication of a second cell carrier frequencyassociated with a second altitude range. In some examples the associatedis predetermined by network management procedure. The network node mayprovide the indication of a first cell carrier frequency associated witha first altitude range and an indication of a second cell carrierfrequency associated with a second altitude range, i.e. theassociations, in a dedicated signal to the wireless device (e.g. UEspecific channel such as PDSCH). or the network node may provide theassociations in a broadcast signal. The broadcast signal may be ageneral system information message or it may be a specific type ofsystem information which is only applicable to specific types ofwireless device. The network node may provide the association in bothsystem information and also certain tailored information dedicated to agiven UE via dedicated control signaling.

The information may be transmitted in one or more cells belonging to F1and/or F2. The information may also be transmitted in one or more cellsoperating on another carrier e.g. F3.

The information about F1 and F2 may be expressed in terms of carrierfrequency identifiers (e.g. channel number, ARFCN, EARFCN, NARFCN etc.).The information about F1 and F2 may be signaled to the UE in the samemessage or in different messages.

The network node may transmit the information to the UE according to anyone or more of the following principles: periodically and occasionally(event basis). The occasional transmission takes place when one or moreconditions or events are triggered or met.

Examples of such conditions are: change in the association between thecarrier and the altitude, when UE altitude changes, when radiotransmission characteristics of signals on F1 and/or F2 change etc.Examples of radio transmission characteristics are beam direction,transmit power, beam width, number of beams per cell etc.

In some embodiments the first altitude range is indicated by a firstaltitude value and a first threshold parameter, wherein the firstthreshold parameter indicates whether the first altitude range is aboveor below the first altitude value; and the second altitude range isindicated by a second altitude value and a second threshold parameter,wherein the second threshold parameter indicates whether the secondaltitude range is above or below the second altitude value.

In some embodiments the second altitude range starts immediately afterthe end of the first altitude range and/or the first altitude range isentirely below the second altitude range.

In step 540, the network node optionally receives from the wirelessdevice, a measurement report comprising at least one radio measurementperformed by the wireless device, wherein the radio measurement is onlyperformed on a signal from a cell operating on the first cell carrierfrequency when the altitude of the wireless device is within the firstaltitude range and only performed on a signal received from a celloperating on the second cell carrier frequency when the altitude of thewireless device is within the second altitude range.

In some embodiments the network node receives from the wireless devicean information about the altitude or the altitude range of the wirelessdevice at which the wireless device performed the at least one radiomeasurement. In some examples the information is received in the samereport message as transmitted for the radio measurements, in otherexamples the information about the altitude or altitude range isreceived in a separate report or protocol message.

In some embodiments the network node provides a data service to thewireless device as a result of the reported radio measurement and/or thereported information about the altitude or the altitude range of thewireless device. Depending on the status of the wireless device (IDLEmode or CONNECTED mode) the response from the network node, e.g. radiobase station will vary. For example the data service may be an initialservice by providing a random access response followed by dedicateresources/physical data channels. In other examples the data service maycomprise additional cells and associated dedicated resources to whichthe wireless device may connect. In other examples the data serviceprovided based on the reported measurements and/or altitude informationmay comprise a Mobile Broadband (MBB) application specifically tailoredto the altitude of the wireless device.

In other examples the network node or radio access initiates cell changeprocedures or handover of the wireless device to a neighbour cell.

In some embodiments the network node commands the wireless device toperforms a radio resource management or a mobility management operationbased on the radio measurement and/or the altitude or the altitude rangeof the wireless device.

In some embodiments the network node uses the results of the radiomeasurements and/or the information about the altitude or the altituderange of the wireless device for performing one or more radiooperational tasks. Examples of such tasks are cell change, positioning,network planning and tuning of parameters, power control etc. Examplesof cell change are handover, RRC connection release with redirection,cell reconfiguration etc.

In some embodiments a wireless device, 110, is configured to perform oneor more of the examples described herein. An example wireless device,600, is depicted in FIG. 6. The wireless device, 600, is suitable forperforming radio measurements in a communications system comprising atleast one network node. In an embodiment the wireless device isconfigured to obtain an indication of a first cell carrier frequencyassociated with a first altitude range and an indication of a secondcell carrier frequency associated with a second altitude range. Thewireless device is further configured to determine the altitude of thewireless device and performs radio measurements depending on thedetermined altitude. The wireless device performs a radio measurement ona signal received from a cell operating on the first cell carrierfrequency only when the altitude of the wireless device is within thefirst altitude range and perform a radio measurement on a signalreceived from a cell operating on the second cell carrier frequency onlywhen the altitude of the wireless device is within the second altituderange.

In some embodiments the wireless device, 600, is further configured toreport the radio measurement to the network node, e.g. to its servingbase station.

In some embodiments the wireless device, 600, is further configured toreport information about its altitude or altitude range to the networknode. The reported altitude or altitude range may be signalled togetherwith the report of the radio measurement. In which case the altitudeinformation may correspond to the altitude of the wireless device atwhich the radio measurement was performed.

In some embodiments the wireless device, 600, is configured to receive adata service from the network node wherein the data service is based onthe reported radio measurements, the reported altitude information orboth.

In other embodiments a network node, for example an eNodeB or gNB, isconfigured to perform one or more of the examples described herein. Anexample network node, 700, is depicted in FIG. 7. The network node, 700,is suitable for managing radio measurements performed by a wirelessdevice, or UE. In an embodiment the network node, 700, is configured todetermine an association of a first cell carrier frequency to a firstaltitude range and an association of a second cell carrier frequency toa second altitude range. The network node is further configured toprovide the wireless device with an indication of the first cell carrierfrequency associated with the first altitude range and an indication ofthe second cell carrier frequency associated with the second altituderange.

In some embodiments the network node, 700, is further configured toreceive, from the wireless device, a measurement report comprising atleast one radio measurement, wherein a radio measurement is onlyperformed on a signal from a cell operating on the first cell carrierfrequency when the altitude of the wireless device is within the firstaltitude range and a radio measurement is only performed on a signalreceived from a cell operating on the second cell carrier frequency whenthe altitude of the wireless device is within the second altitude range.

In other embodiments the network node is further configured to receivefrom the wireless device an information about the altitude or thealtitude range of the wireless device at which the wireless deviceperformed the at least one radio measurement.

In some examples the network node receives the information about thealtitude of the wireless device in the same message as the radiomeasurement report.

In other embodiments the network node, 700, performs one or more actionsbased on the received radio measurements and/or altitude information.For example, the network node. 700, may provide or adapt a data serviceto the wireless device. In other examples the network node commands thewireless device to change cells or provides the wireless device withadditional cells.

In some embodiments an apparatus is provided suitable for performingradio measurements in a communications system is provided. An example isdepicted in FIG. 8. The apparatus, 800, comprises a processor, 810, amemory, 820, and a transceiver circuit, 830. The transceiver circuit,830, is configured to obtain an indication of a first cell carrierfrequency associated with a first altitude range and an indication of asecond cell carrier frequency associated with a second altitude range.The processor, 810, is executable to determine the altitude of thewireless device. The transceiver circuit, 830, is further configured toperform a radio measurement on a signal received from a cell operatingon the first cell carrier frequency only when the altitude of thewireless device is within the first altitude range and perform a radiomeasurement on a signal received from a cell operating on the secondcell carrier frequency only when the altitude of the wireless device iswithin the second altitude range.

Said apparatus, 800, may be further configured to perform any otherexample disclosed herein.

In other embodiments an apparatus is provided suitable for managingradio measurements performed by a wireless device in a communicationsnetwork is provided. An example apparatus, 900, is depicted in FIG. 9.The apparatus, 900, comprises a processor, 910, a memory, 920, and atransceiver circuit, 930. The processor is configured to determine anassociation of a first cell carrier frequency to a first altitude rangeand an association of a second cell carrier frequency to a secondaltitude range. The transceiver circuit, 930, is configured to provide,to a wireless device, an indication of a first cell carrier frequencyassociated with a first altitude range and an indication of a secondcell carrier frequency associated with a second altitude range.

In other embodiments the transceiver circuit, 930, is further configuredto receive, from the wireless device, a measurement report comprising atleast one radio measurement, wherein a radio measurement is onlyperformed on a signal from a cell operating on the first cell carrierfrequency when the altitude of the wireless device is within the firstaltitude range and a radio measurement is only performed on a signalreceived from a cell operating on the second cell carrier frequency whenthe altitude of the wireless device is within the second altitude range.

In other embodiments the apparatus, 900, uses the results of the radiomeasurements and/or the information about the altitude or the altituderange of the wireless device for performing one or more radiooperational tasks. Examples of such tasks are cell change, positioning,network planning and tuning of parameters, power control etc. Examplesof cell change are handover, RRC connection release with redirection,cell reconfiguration etc. In other examples the apparatus 900, mayprovide or adapt a data service to the wireless device.

In some embodiments a wireless device control application, 1000,comprises a transceiver module, 1010, a determination module, 1020, anda measurement module, 1030. An example of such a wireless device isdepicted in FIG. 10. The Transceiver module, 1010, is configured toobtain an indication of a first cell carrier frequency associated with afirst altitude range and an indication of a second cell carrierfrequency associated with a second altitude range. The determinationmodule, 1020, is configured to determine the altitude of the wirelessdevice. The transceiver module, 1010, is configured to perform a radiomeasurement on a signal received from a cell operating on the first cellcarrier frequency only when the altitude of the wireless device iswithin the first altitude range and perform a radio measurement on asignal received from a cell operating on the second cell carrierfrequency only when the altitude of the wireless device is within thesecond altitude range.

Said wireless device control application, 1000, may comprise theaforementioned modules and/or other modules configured to perform anyother example disclosed herein.

In other embodiments a network node control application, 1100, comprisesa transceiver module, 1110, and a determination module, 1120. An exampleof such a network node is depicted in FIG. 11. The determination module,1120, is configured to determine an association of a first cell carrierfrequency to a first altitude range and an association of a second cellcarrier frequency to a second altitude range. The transceiver module,1110, is configured to provide, to a wireless device, an indication of afirst cell carrier frequency associated with a first altitude range andan indication of a second cell carrier frequency associated with asecond altitude range.

In further embodiments the transceiver module, 1110, is furtherconfigured to receive, from the wireless device, a measurement reportcomprising at least one radio measurement, wherein a radio measurementis only performed on a signal from a cell operating on the first cellcarrier frequency when the altitude of the wireless device is within thefirst altitude range and a radio measurement is only performed on asignal received from a cell operating on the second cell carrierfrequency when the altitude of the wireless device is within the secondaltitude range.

Said network node control application, 1100, may comprise theaforementioned modules and/or other modules configured to perform anyother example disclosed herein.

It should be noted that the above-mentioned examples illustrate ratherthan limit the invention, and that those skilled in the art will be ableto design many alternative embodiments without departing from the scopeof the appended claims. The word “comprising” does not exclude thepresence of elements or steps other than those listed in a claim, “a” or“an” does not exclude a plurality, and a single processor or other unitmay fulfil the functions of several units recited in the claims. Anyreference signs in the claims shall not be construed so as to limittheir scope.

It will be apparent to the skilled person that the exact order andcontent of the actions carried out in the method described herein may bealtered according to the requirements of a particular set of executionparameters. Accordingly, the order in which actions are described and/orclaimed is not to be construed as a strict limitation on order in whichactions are to be performed. Any disclosure of an individual embodimentdoes not preclude the combination of features of that embodiment withanother embodiment disclosed herein.

1. A method performed by a user equipment (UE), the method comprising:receiving one or more parameters which indicates an association betweenan altitude and a cell carrier frequency, wherein the one or moreparameters comprises information to enable the UE to determine whetherit is allowed to perform a measurement on a reference signal associatedwith the cell based on the altitude of the UE; and reporting a radiomeasurement performed on the reference signal when the UE is determinedto be at an altitude where the UE is allowed to perform the measurementthe measurement report further comprising reporting an information aboutthe altitude or the altitude range of the UE at which the UE performedthe radio measurement.
 2. The method of claim 1, wherein the cellcarrier frequency is a first cell carrier frequency and the one or moreparameters comprise a first altitude range associated with the firstcell carrier frequency and is indicated by a first altitude value and afirst threshold parameter, wherein the first threshold parameterindicates whether the first altitude range is above or below the firstaltitude value and a second altitude range associated with a second cellcarrier frequency is indicated by a second altitude value and a secondthreshold parameter, wherein the second threshold parameter indicateswhether the second altitude range is above or below the second altitudevalue and the reported radio measurement comprises a measurementperformed on reference signals associated with one or both of the firstand second cell carrier frequencies when the UE is determined to be atan altitude where the UE is allowed to perform the measurement on thereference signals of the first and second cell carrier frequencies. 3.The method of claim 2, wherein the second altitude range startsimmediately after the end of the first altitude range and/or the firstaltitude range is entirely below the second altitude range.
 4. Themethod of claim 1, further comprising receiving a data service from thenetwork node wherein the data service is based on the reported radiomeasurement and/or the reported information about the altitude or thealtitude range of the UE.
 5. The method of claim 1, wherein the UE isconfigured to perform a radio resource management or a mobilitymanagement operation based on the radio measurement and/or the altitudeor the altitude range of the UE.
 6. A method performed by a network nodefor managing radio measurements performed by a UE in a communicationsnetwork, the method comprising: providing the UE with one or moreparameters which indicates an association between an altitude and a cellcarrier frequency, wherein the one or more parameters comprisesinformation to enable the UE to determine whether it is allowed toperform a measurement on a reference signal associated with the cellbased on the altitude of the UE; receiving a measurement reportcomprising a radio measurement performed on the reference signal whenthe UE is determined to be at an altitude where it is allowed to performthe measurement, further comprising receiving from the UE an informationabout the altitude or the altitude range of the UE at which the UEperformed the radio measurement.
 7. The method of claim 6, wherein thecell carrier frequency is a first cell carrier frequency and the one ormore parameters comprise a first altitude range associated with thefirst cell carrier frequency and is indicated by a first altitude valueand a first threshold parameter, wherein the first threshold parameterindicates whether the first altitude range is above or below the firstaltitude value and a second altitude range associated with a second cellcarrier frequency is indicated by a second altitude value and a secondthreshold parameter, wherein the second threshold parameter indicateswhether the second altitude range is above or below the second altitudevalue and the reported radio measurement comprises a measurementperformed on reference signals associated with one or both of the firstand second cell carrier frequencies when the UE is determined to be atan altitude where the UE is allowed to perform the measurement on thereference signals of the first and second cell carrier frequencies. 8.The method of claim 6, further comprising determining the association ofthe cell carrier frequency to the altitude based on one or more of: cellcoverage; beam characteristics; frequency range or band; or antennacharacteristics.
 9. A user equipment (UE) for performing radiomeasurements in a communications system, the UE configured to: receiveone or more parameters which indicates an association between analtitude and a cell carrier frequency, wherein the one or moreparameters comprises information to enable the UE to determine whetherit is allowed to perform a measurement on a reference signal associatedwith the cell based on the altitude of the UE; and report a radiomeasurement performed on the reference signal when the UE is determinedto be at an altitude where the UE is allowed to perform the measurement,further comprising reporting an information about the altitude or thealtitude range of the UE at which the UE performed the radiomeasurement.
 10. The UE of claim 9, wherein the cell carrier frequencyis a first cell carrier frequency and the one or more parameterscomprise a first altitude range associated with the first cell carrierfrequency and is indicated by a first altitude value and a firstthreshold parameter, wherein the first threshold parameter indicateswhether the first altitude range is above or below the first altitudevalue; and a second altitude range associated with a second cell carrierfrequency which is indicated by a second altitude value and a secondthreshold parameter, wherein the second threshold parameter indicateswhether the second altitude range is above or below the second altitudevalue and the reported radio measurement comprises a measurementperformed on reference signals associated with one or both of the firstand second cell carrier frequencies when the UE is determined to be atan altitude where the UE is allowed to perform the measurement on thereference signals of the first and second cell carrier frequencies. 11.The UE of claim 10, wherein the second altitude range starts immediatelyafter the end of the first altitude range and/or the first altituderange is entirely below the second altitude range.
 12. The UE of claim9, wherein the UE is configured to receive a data service from thenetwork node wherein the data service is based on the reported radiomeasurement and/or the reported information about the altitude or thealtitude range of the UE.
 13. The UE of claim 9, wherein the UE isconfigured to perform a radio resource management or a mobilitymanagement operation based on the radio measurement and/or the altitudeor the altitude range of the UE.
 14. A network node for managing radiomeasurements performed by a user equipment, UE, in a communicationsnetwork, the network node is configured to: provide the UE with one ormore parameters which indicates an association between an altitude and acell carrier frequency, wherein the one or more parameters comprisesinformation to enable the UE to determine whether it is allowed toperform a measurement on a reference signal associated with the cellbased on the altitude of the UE; and receive a measurement reportcomprising a radio measurement performed on the reference signal whenthe UE is determined to be at an altitude where it is allowed to performthe measurement, further receiving from the UE an information about thealtitude or the altitude range of the UE at which the UE performed theat least one radio measurement.
 15. The network node of claim 14,wherein the cell carrier frequency is a first cell carrier frequency andthe one or more parameters comprise a first altitude range associatedwith the first cell carrier frequency and is indicated by a firstaltitude value and a first threshold parameter, wherein the firstthreshold parameter indicates whether the first altitude range is aboveor below the first altitude value and a second altitude range associatedwith a second cell carrier frequency is indicated by a second altitudevalue and a second threshold parameter, wherein the second thresholdparameter indicates whether the second altitude range is above or belowthe second altitude value and the reported radio measurement comprises ameasurement performed on reference signals associated with one or bothof the first and second cell carrier frequencies when the UE isdetermined to be at an altitude where the UE is allowed to perform themeasurement on the reference signals of the first and second cellcarrier frequencies.
 16. The network node of claim 14, wherein thenetwork node is configured to determine the association of the cellcarrier frequency to the altitude based on one or more of: cellcoverage; beam characteristics; frequency range or band; or antennacharacteristics.